Control method for robot and robot system

Abstract

In a control method for a robot including a manipulator and a force detector that detects an external force acting on the manipulator on three detection axes orthogonal to one another, a direction of the external force is detected by the force detector, and a degree of freedom of motion of a tool center point set for the manipulator according to the external force is limited based on the direction of the external force.

What is claimed is: 
     
       1. A control method for a robot including a manipulator and a force detector that detects an external force acting on the manipulator on three detection axes orthogonal to one another, comprising:
 detecting a direction of the external force by the force detector; and 
 limiting motion of a tool center point set for the manipulator according to the external force to one degree of freedom based on the direction of the external force by controlling the external force acting on the tool center point to be a predetermined target force, when the largest value of the magnitude of the respective components of the external force on the three detection axes of the force detector is larger than a product of the second largest value and a first constant. 
 
     
     
       2. A robot system comprising:
 a robot including a manipulator and a force detector that detects an external force acting on the manipulator on three detection axes orthogonal to one another; and 
 a processor programmed to detect a direction of the external force by the force detector, and limits motion of a tool center point set for the manipulator according to the external force to one degree of freedom based on the direction of the external force by controlling the external force acting on the tool center point to be a predetermined target force, when the largest value of the magnitude of the respective components of the external force on the three detection axes of the force detector is larger than a product of the second largest value and a first constant. 
 
     
     
       3. The control method for the robot according to  claim 1 , further comprising:
 limiting motion of the tool center point set according to the external force to two degrees of freedom when the largest value of the magnitude of the respective components of the external force on the three detection axes of the force detector is smaller than a product of the second largest value and a second constant and the second largest value is larger than a product of the smallest value and a third constant.